Motor assembly with gear housing containing pinion gear support bearing

Abstract

The invention is a compact gear drive with a maximum transmission range for a constant crown gear diameter and constant axial displacement. A pinion is mounted on a bearing remote from the crown gear. The pinion is constructed as a hollow shaft and is fictionally connected to a drive shaft of a driving motor.

We claim: 
     
       1. A motor assembly comprising: a motor having a drive shaft which rotates during activation of the motor;   a gear housing attached to the motor;   a gear and a pinion meshing with the gear, the gear and the pinion being located within the gear housing with the gear driving a power takeoff; and   a bearing, mounted in the gear housing at a position displaced from the toothed gear, for rotatably supporting rotation of the pinion during activation of the motor; and wherein   the pinion has a hollow shaft with the hollow shaft engaging an outside surface of the drive shaft for directly driving the pinion.   
     
     
       2. A motor assembly in accordance with claim 1 further comprising: a radial shaft packing mounted in the gear housing concentric with the pinion and outboard from the bearing.   
     
     
       3. A motor assembly in accordance with claim 1 further comprising: a shoulder in the gear housing;   an interior groove in the gear housing; and   a snap ring inserted in the groove; and wherein   the bearing is axially retained in the gear housing between the shoulder and the snap ring.   
     
     
       4. A motor assembly in accordance with claim 1 wherein: the pinion is retained axially in the bearing by a retaining mechanism.   
     
     
       5. A motor assembly in accordance with claim 3 wherein the retaining mechanism comprises: a shoulder in the pinion which prevents the bearing from moving axially past the shoulder;   a groove formed in the pinion; and   a snap ring retained in the groove which prevents the bearing from moving axially past the snap ring.   
     
     
       6. A motor assembly in accordance with claim 5 wherein the retaining mechanism further comprises: a supporting disk disposed between the shoulder and the bearing.   
     
     
       7. A motor assembly in accordance with claim 1 wherein: the gear housing is symmetrical with reference to an axis of rotation of the gear with the axis of rotation of the gear being orthogonal to an axis of rotation of the pinion.   
     
     
       8. A motor assembly in accordance with claim 1 further comprising: a pair of bearings for rotatably supporting a shaft attached to the toothed gear with the bearings being located symmetrically in the gear housing relative to the axis of rotation of the pinion.   
     
     
       9. A motor assembly in accordance with claim 8 further comprising: a pair of grooves in the bearing housing, a first of the pair of grooves being outboard of one of the pair of bearings for rotatably supporting the shaft attached to the gear and a second of the pair of grooves being outboard of another one of the pair of bearings for rotatably supporting the shaft attached to the gear; and   a pair of snap rings for retaining the pair of bearings one of the pair of snap rings being retained in the first of the pair of grooves and another one of the pair of snap rings being retained in the second of the pair of grooves.   
     
     
       10. A motor assembly in accordance with claim 1: a flange for retaining a bearing which rotatably supports a shaft driven by the gear; and   fasteners attaching the flange to the gear housing.   
     
     
       11. A motor assembly in accordance with claim 1 further comprising: a shaft driven by the gear, the shaft having at least two different steps each having a different diameter, a largest diameter of the shaft being adjacent to an axis of rotation of the pinion.   
     
     
       12. A motor assembly in accordance with claim 1 further comprising: a shaft having the gear mounted on a support area of the shaft, a shoulder having a diameter larger than a diameter of the support area retaining the gear against axial movement in a first axial direction and a bearing rotatably supporting the shaft for rotation in the housing and retaining the gear against axial movement in a second axial direction opposite the first axial direction.   
     
     
       13. A motor assembly in accordance with claim 1 further comprising: only one other bearing rotatably supporting the drive shaft, the one other bearing being mounted at an end of the motor opposite an end of the motor nearest the gear housing and the bearing.   
     
     
       14. A motor assembly in accordance with claim 1 wherein: the gear is a crown gear and a ratio between a diameter of the gear and an axial displacement between the pinion axis is between 2.5 and 5.   
     
     
       15. A motor assembly in accordance with claim 2 wherein: the gear is a crown gear and a ratio between a diameter of the gear and an axial displacement between the pinion axis is between 2.5 and 5.   
     
     
       16. A motor assembly in accordance with claim 3 wherein: the gear is a crown gear and a ratio between a diameter of the gear and an axial displacement between the pinion axis is between 2.5 and 5.   
     
     
       17. A motor assembly in accordance with claim 4 wherein: the gear is a crown gear and a ratio between a diameter of the gear and an axial displacement between the pinion axis is between 2.5 and 5.   
     
     
       18. A motor assembly in accordance with claim 14 wherein: the gear is a crown gear and a ratio between a diameter of the gear and an axial displacement between the pinion axis is between 2.5 and 5.   
     
     
       19. A motor assembly comprising: a motor having a drive shaft which rotates during activation of the motor;   a gear housing attached to the motor;   a gear and a pinion meshing with the gear, the gear and the pinion being located within the gear housing with the gear driving a power takeoff;   only one bearing, mounted in the gear housing at a position displaced from the gear, for rotatably supporting rotation of the pinion during activation of the motor;   only one other bearing displaced axially along the motor from the only one bearing which rotatably supports the drive shaft; and wherein   the pinion has a hollow shaft with the hollow shaft engaging an outside surface of the drive shaft for directly driving the pinion.